Added ability to select anchors with mouse

src/Graphic/Graphic.coffee

@@ -34,7 +34,7 @@ class Graphic.Element
     viewMatrix:
 
     highlight(graphic): A function that takes in a graphic and returns either
-    a color or null.
+    a {color, lineWidth} object or null.
 
     ###
     throw "Not implemented"
@@ -94,7 +94,31 @@ class Graphic.Group extends Graphic.Element
 
 
 class Graphic.Anchor extends Graphic.Element
+  render: (opts) ->
+    @highlightIfNecessary(opts)
+
+  hitDetect: (opts) ->
+    {x, y, viewMatrix} = opts
+    [myX, myY] = viewMatrix.compose(@matrix).origin()
+    distSq = (x - myX) * (x - myX) + (y - myY) * (y - myY)
+    if distSq <= @highlightRadius * @highlightRadius
+      return [@particularElement]
+    else
+      return null
+
+  highlightIfNecessary: ({highlight, ctx, viewMatrix}) ->
+    return unless highlight
+    highlightSpec = highlight(this)
+    if highlightSpec
+      ctx.save()
+      ctx.beginPath();
+      [myX, myY] = viewMatrix.compose(@matrix).origin()
+      ctx.arc(myX, myY, @highlightRadius, 0, 2 * Math.PI, false)
+      ctx.fillStyle = highlightSpec.color
+      ctx.fill()
+      ctx.restore()
 
+  highlightRadius: 5
 
 
 
@@ -104,7 +128,19 @@ class Graphic.Path extends Graphic.Element
     @performPaintOps(opts)
     @highlightIfNecessary(opts)
 
+    # Render anchor highlights, if necessary
+    for childGraphic in @childGraphics
+      childGraphic.render(opts)
+
   hitDetect: (opts) ->
+    # Check for anchor hits
+    latestHit = null
+    for childGraphic in @childGraphics
+      latestHit = childGraphic.hitDetect(opts) ? latestHit
+    if latestHit
+      console.log('path hit anchor!')
+      return latestHit.concat(@particularElement)
+
     opts.ctx = getDummyCanvasCtx()
     {ctx, x, y} = opts
     @buildPath(opts)

src/Model/Element.coffee

@@ -170,6 +170,8 @@ module.exports = Element = Node.createVariant
 
   matrix: ->
     matrix = new Util.Matrix()
+    for position in @childrenOfType(Model.Position)
+      matrix = matrix.compose(position.matrix())
     for transform in @childrenOfType(Model.Transform)
       matrix = matrix.compose(transform.matrix())
     return matrix

src/Model/Model.coffee

@@ -92,6 +92,28 @@ Model.Transform.addChildren [
 ]
 
 
+Model.Position = Model.Component.createVariant
+  label: "Position"
+  matrix: ->
+    {x, y} = @getAttributesValuesByName()
+    return Util.Matrix.naturalConstruct(x, y, 1, 1, 0)
+  defaultAttributesToChange: ->
+    {x, y} = @getAttributesByName()
+    return [x, y]
+  controllableAttributes: ->
+    {x, y} = @getAttributesByName()
+    return [x, y]
+  controlPoints: ->
+    {x, y} = @getAttributesByName()
+    return [
+      {point: [0, 0], attributesToChange: [x, y], filled: true}
+    ]
+
+Model.Position.addChildren [
+  createAttribute("X", "x", "0.00")
+  createAttribute("Y", "y", "0.00")
+]
+
 
 Model.Fill = Model.Component.createVariant
   label: "Fill"
@@ -122,19 +144,25 @@ Model.Shape.addChildren [
 ]
 
 
+Model.Point = Model.Element.createVariant()
+Model.Point.addChildren [
+  Model.Position.createVariant()
+]
+
+
 Model.Group = Model.Shape.createVariant
   label: "Group"
   graphicClass: Graphic.Group
 
 
-Model.Anchor = Model.Shape.createVariant
+Model.Anchor = Model.Point.createVariant
   label: "Anchor"
   graphicClass: Graphic.Anchor
 
 createAnchor = (x, y) ->
   anchor = Model.Anchor.createVariant()
-  transform = anchor.childOfType(Model.Transform)
-  attributes = transform.getAttributesByName()
+  position = anchor.childOfType(Model.Position)
+  attributes = position.getAttributesByName()
   attributes.x.setExpression(x)
   attributes.y.setExpression(y)
   return anchor